<?php
/**
 * Created by PhpStorm.
 * User: lidan
 * Date: 2018/10/8
 * Time: 下午1:04
 */

namespace Imooc;

/**
 * 事件观察者接口
 * Interface Observer
 * @package Imooc
 */
interface Observer
{
    function update($event_info = null);
}